This invention relates generally to cardiac pacing and in particular to external, non-invasive cardiac pacing.
External non-invasive cardiac pacing is a well established technique which can provide effective heart pacing on an emergency basis. Traditionally, the pain and undesirable stimulation of skeletal muscles associated with non-invasive pacing have limited the acceptance of this technique.
Recent external pacemaker designs, such as that disclosed in U.S. Pat. No. 4,349,030 issued to Belgard et al, have addressed the problem of pain associated with external non-invasive pacing by providing constant current pacing pulses of extended duration. Typically, these pulses are 20 to 40ms in length and maintain a relatively constant current level throughout the duration of the pulse.